Conventionally, a wireless communication terminal used for a communication system of a time division multiple access system (hereinafter arbitrarily abbreviated as TDD/TDMA system) includes one radio unit and communicates wirelessly with a base station. However, communication using one radio unit limits the communication speed. Therefore, it is considered recently to improve the communication speed by providing one wireless communication terminal with a plurality of radio units and thus increasing the number of slots used in the same frame.
As above, in order to communicate with one base station by providing one wireless communication terminal with a plurality of radio units, it is necessary that every radio unit is respectively synchronized with the base station. In this case, it is conceivable that each radio unit is regarded as an individual wireless communication terminal and the distance from the base station and delay time due to fading are measured through a control channel for each radio unit, so that each wireless terminal is independently synchronized with the base station as to frame transmission timing. It is noted that as a synchronization method for a wireless communication terminal having one radio unit is known one disclosed in Japanese Patent Application Laid-Open Publication No. 07-154383, for example.
However, when a plurality of radio units held by one wireless communication terminal use a control channel individually, the number of control channels for one terminal increases. Thus, it becomes impossible, with limited number of channels, to respond to this increase in the number of channels used, so that it is supposed that the number of terminals which can be held by the base station decreases. When the number of control channel resources used by one radio unit is 1, for example, the number of control channel resources used by a wireless communication terminal provided with N radio units is N. When communication of TDMA system is performed, the number of control channels per unit time is fixed. Therefore, when a wireless communication terminal provided with N radio units uses N times of control channel resources, the number of wireless communication terminals capable of frame synchronization with the base station decreases to 1/N.